Apparatus for surveying boreholes



Feb. 1s, 1941; A. RT BARNETT 2,232,360

APPARATUS FOR SURVEYING BOREHOLES Filed 001;. 18, 1937 4 Sheets`Sheet 1 Feb. 18, 1941. A, R, BARNETT 2,232,360

APPARATUS FOR SURVEYING BOREIHOLESI Filed Oct. 18, 1937 y 4 Sheets-Sheet 2 Feb,`18, 1941. A. R. BARNET'T 22323515 APPARATUS FOR SURVEYNG BOREHOLES 9121 ujf-7 11p 13j 125 Feb. 1s, 1941. A, R, BARNETT -2,232,360

APPARATUS FOR SURVEYING BOREHOLES Filed Oct. 18, 19157r 4 SheebS--Sheefl magi nlIl

Patented Feb. 1s, 1941 PATENT oFFlcs APPARATUS FOR SURVEYING BOREHOLES Arthur R. Barnett, Los Angeles, Calif., assignor of one-third to Joe W. Culbertson, Los Angeles, Calif., and one-third to Technical Oil Tool Corporation, a. corporation of California Application October 18, 1937, Serial No. 169,614

Claims.

My invention relates to methods of and apparatus for surveying boreholes such as oil wells, and it has particular reference to methods and apparatus by which a borehole is surveyed through use of instruments within the drill pipe.

In accordance with previous methods and apparatus, it is necessary to lower on a line or drop into the'drill pipe, a single surveying instrument which measures and records or indicates the degree of inclination of the hole from the vertical;

or two instruments, one sensitive to degree of inclination, and the other sensitive to direction of inclination. To gain access to and read the instrument or instruments under the drop method, it is necessary to withdraw the entire drill pipe, or lower an overshot and withdraw the instrument on line.

Under that line method where an indicating or recording instrument is permanently situated n at the surface of the well and the actual surveying instrument is lowered into the drill pipe on a line,` it is necessary to withdraw the -surveying instrument after each survey in order that the instrument may not be damaged upon continued drilling or operation of the drill pipe and iiuid circulation interfered with. Under another line method, where the instrument lowered into the drill pipe not only surveys but records, it is, likewise, necessary to withdraw the instrument fol- -lowing each survey to avoid instrument damage and drilling interference. Y

In spite of the innumerable dimculties presented in the perfomance of the above described meth- P ods, they have been adhered to for want of a method as embodied in my invention which eliminates dropping and recovering by withdrawal of the drill pipe, or. the use of a line,` and yet a survey of the hole at any point desired in the drilling thereof can be instantly and accurately made upon .bringing the drill pipe momentarily to a standstill.

It is a purpose of my invention to provide a method and apparatus for surveying boreholes by the permanent positioning in the drill pipe so 'Y as not to interfere with fluid circulation, of a survey instrument which supplies electric current modied in' accordance with the survey, to a registering or recording instrument at the top or surface of the hole, which is sensitive to such current modifications to register or record the survey Amade by the survey instrument.

It is also a purpose of my invention to provide a method of and apparatus for surveying boreholes through the drill pipe by the permanent (ci. ass-1) strument and further modified in accordance with direction of -deviation by the other instrument, to a. registering or recording instrument situated at the surface of the hole and sensitive to both current modifications so as to register or record the two surveys made by the surveying instrlmients.

A further purpose of my invention is the provision of a drill pipe havingpermanently secured therein but insulated therefrom, one or more ele'ctrical conductors for cooperation with the drill pipe when using a single conductor, or independently thereof when using a plurality of conductors to form an electrical circuit by which current is conducted from the survey instrument orinstruments in the drill pipe, to the registering or recording instrument at Ythe surface of the hole. Each conductor is made in sections corresponding in number to the sections of the drill pipe, and the ends of each conductor section are provided with electrical connectors by which the conductor sections are electrically connected one to the other or disconnected one from the other according as the pipe sections are connected to or disconnected from each other.

In the accompanying drawings wherein two embodiments of my invention are illustrated- Figure 1 is a view showing vertical section and partly in elevation a drill pipe having applied thereto certain elements embodied in the apparatus.

Fig. 1A is a transverse sectional view taken on the line lA-lA of Figure 1.

Figure 2 is an enlarged transverse sectional view taken on the line 2 2 of Figure 1.

Figure 3 is a viewsimilar to Figure 2 taken on the line 2 2 of Figure 1. Y f

-Figure 4 is aview similar to Figure 3 taken on the line 4 4 of Figure 1.

Figure 5 is a vertical sectional view taken on the line 5 5 of Figure 2. v

Figure 6 is a vertical sectional view taken on the line 6 6 of Figure 4.

Figure l is a. vertical sectional view taken on the line 1 1 of Figure 4.

Figure '7A is an enlarged sectional fragmentary view of the pin end of the sub, showing the corresponding connector.

Figure 8l is a vertical sectional view showing the survey instrument and control means therefor, of one form of surveying apparatus embodying my invention.

Figure 9 is a transverse sectional view taken on the line 9 9 of Figure 8.

Figure 10 is a view similar to Figure 8 but taken at right angles thereto.

Figure 11 is a view showing diagrammatically the elements and circuits embodied in the apparatus shown in the preceding views.

Figure 12 is a view showing in side elevation another form of surveying instrument embodying my invention.

Figure 13 is, a view similar to Figure 8 showing a second form of surveying instrument and control means therefor, included in a second form of surveying apparatus embodying my invention.

Figure 14 is a view similar to Figure 13 `but taken at right angles thereto.

Figure 15 is a transverse sectional view taken on the line I5-I5 of Figure 13.

Figure 16 is a transverse sectional view taken on the line lli-I6 of Figure 14.

Figure 17 is a view showing another posi-tion of the levers shown in Figure 14.

Figure 18 is a vertical sectional View taken on the line |8-l8 of Figure 14.

Figure 19 is a transverse sectional view taken on the line I 9-I 9 of Figure 14.

Figure 20 is a transverse sectional view taken on the line 20-20 of Figure 14.

Figure 21 is a transverse sectional view taken on the line 2 |-2I of Figure 14.

Figure 22 is a transverse sectional view 'taken on the line 22-22 of Figure 14.

Figure 23 is a view showing diagrammatically the elements of the second form of surveying apparatus and the circuits therefor.

.One method embodied in my invention comprises the permanent positioning in a drill pipe of a surveying instrument sensitive only to maximum deviation of a borehole from the ver-tical and operable to modify electric current as `conducted to an electrical calibrated instrument situated at the top of the borehole, in accordance with maximum deviation, whereby the electrical instrument is caused to register or indicate such deviation.

The apparatus by which this method is performed, is shown in Figures 1 to 11, with the structural details of the surveying instrument in the -drill pipe and its central means, illustrated in Figures 8, 9 and 10. As here shown, a case 25 is closed at its lower end by a screw plug 26, while its upper end is formed with a central opening 21. A partition 28 is secured in the case above the plug 26 and between the two is conned the winding 29 of :a solenoid S. The core 30 of the solenoid is movable vertically in a sleeve 3|, the lower end of which extends into a recess 32, while its upper end is formed with a ange 33 provided with a lug 34 engaging a collar 30 i'lxed on the core 30 to limit upward movement of the latter. Fixed in the recess is a stud 35 surrounded by a spring 36, the stud limitingi downward movement' of the core and the spring: urging the core upwardly against the lug 34.

On the upper end of .the core 30 is pivoted a@ pawl 31 urged into engagementwith a ratchet wheel 38 xed centrally to a shaft 39 journaled in trunnions 40 fixed to the partition 28. Also xed to the shaft 39 are a pair of cam wheels 4|, 4| each provided cams 42 and intervening depressions 43, al1 of which are formed with notches 44 to prevent the wheels accidentally turning when engaged by a pair of cams 45, 45.

A second partition 46 is fixed in the case 25 and it is formed with two slots 46a, 46a in which the cams 45, move. Centrally the partition is formed with a stud 41 extending vinto an opening 48 of a centering head 49. On the lower side of this head the cams 45, 45 are formed, and the head together with the cams are movable vertically on rods 50 secured at their lower ends in the partition 46.

A pointed pin 5I extends upwardly from the stud 41 to engage the apex of a conical bearing 52 of the conical weight 53 of a pendulum D. This pendulum includes a rod 54 xed to the apex of the Weight and having at its upper end a sleeve 55 containing a contact 56 pressed uppendulum on its supporting pin 5l.

The commutator C comprises a body 58 of insulating material having a concave underside concentric to the pendulum pivot. Within this body is a central contact 59 and a plurality of f ring contacts 60. By means of lconductors 6|, the contacts 59 and 60 are individually connected to resistance coils 62 supported on a drum 63 of insulating material suitably secured Within the case 25. The coils are connected in series, ancl the uppermost coil is connected to an insulatef; conductor or wire 64 which extends upwardly through the opening 21 and downwardly in the case where it is connected to one end of the winding 29.

In the operation of the surveying instrument, and the control means therefor, just described, the cams 45 normally repose on certain of the wheel cams 42, so that the head 49 is elevated, as shown in Figures 8 and l0, to support the pendulum D in an elevated position inwhich its weight is lifted off the pivot pin 5I. By virtue of the surfaces 49a and 53a, the pendulum as supported is centered to cause the contact '56 to engage the commutator contact 59. Thus, the pendulum is secured against movement and clear of its pivot 5I to prevent possible damage thereto.

When the solenoid S is energized through a circuit which will be later described, the core 30 is drawn downwardly against the tension of the spring 36 to move the pawl 31 downwardly and thus rotate the ratchet wheel 38 Ia distance corresponding to the length of one tooth thereof. Under this movement the cam wheels 4| are rotated to cause the cams 42 to pass out of engagement with the cams 45 and the latter into engagement with the depressions 43. Thus the head 49 is now lowered onto the partition 46 to permit the pendulum D to rest on the pivotpin 5| and the weight 53 to clear the head, so that the pendulum is now free to respond to any maximum deviation from the vertical.

According to the angular position assumed by the pendulum once it is released', determines that contact ring engaged by the contact 56, and; hence, determines the number of resistance coils included in the circuit of which the pendulum forms a part, it being clear that when the pendulum is vertical the center contact 59 is engaged to include all coils in the circuit. In this manner the surveying instrument is sensitive to modify actuated to cause the wheel cam 42 to engage the head cams 46 and lift the head v49, thereby elevating the pendulum ofi its pivot. At the same time the pendulum is swung to the centered position through coaction of the surface 49 and 63, so that the pendulum is now locked in centered position and elevated with respect to its pivot.

According to th'e foregoing operation ofthe pendulum control means, the pendulum is lowered .and released, and then elevated, centered and locked as the solenoid is successively ener- In Figure 12, I'have shown another form of surveying instrument of the pendulum type which is designed to amplify current modifications so that minutes of degrees as well as degrees of deviation can be registered by my apparatus. A partition 66 corresponds to the partiposed in staggered relation at theperiphery of tion 46, .and it is formed with a pivot pin 66 engaging a bearing in the Weight 61 of a pendulum having a rod 69 provided at its upper end `with a disk 69. Y

The disk 69 abuts a. companion disk 19 .xed on the lower end of a rackbar 1| whichis suitably guided in its vertical movement. The rack bar meshes with a pinion 12 fixed to a shaft 19 lwith a gear 14 which meshes with a pinion`16 'ilxed to a shaft 16. A wheel type of commutator 11 isixed tov the shaft 16, and it has a multiplicity of resistance units therein connected in series and having the terminals 18 thereof exthe Wheel,for.fcontact with a radial brush 19 whichv may be connected to the wire 64 when-the present instrument is substituted for the one veus ' lcordlngly vary the resistanceinterposed in a circuit to modify current owing through the cir- `vcuit to a registerable degree no matter how small the degree lof deviation as indicated by the pendulum. g Referring now to Figure `1, a rotary drill pipe is shown as comprising a sub B, a bit T, and one of any number of pipe sections P. The pipe section is connected to the4 sub by a pin and box type of tool joint J, and by a similar Joint J the pipe section is connected to anupper and noncircular pipe section 'P' which' is adapted to extend through a rotary table for rotating the drill pipe in the usual manner. The s ub B isvrormed vwith two diametrically arranged thickened portions 89 and 8| and the portion 99 is formed with a pocket 92 in .which the apparatus shown in Figure 8 is adapted to be received.

The case 26 is confined in the pocket 99 by a screwplug 94 applied before the bit T is connected to the sub. Suitable cushioning members, such as the springs 96, 96, are positioned at the ends of the case to protect the apparatus against shock. Y

With the surveying instrument and its a purtenances located in thesub, it becomes clear that the instrument is permanently positioned therein during` all drilling operations.

To counterbalance the weight of theinstrumentand its appurtenances the thickened portion 9| is provided, and thus the weight of the instrument is ineective to produce any eccentric motion of the drill pipe when rotated. v

To conduct electrical current to the surveying .instrument and the solenoid S from a source at the surface of the-well and through a circuit which preferably, but not necessarily, includes the drill pipe, certain conductors and connectors have been provided which are permanent parts of the drill pipe, yet vpermitting easy connection and disconnection of the pipe parts when and as required.

As shown in Figures 1 and 2, the upper pipe section P' is provided with a collar 96 having a circular periphery to which is secured a ring 91 of insulation. This ring is surrounded by a collector, ring 89 engaged by a stationary brush 69. A second collector'ring 99 is secured directly v Each conductor section comprises a wire 92 covered by insulation 99 and encased in a metal conduit 99 welded or otherwise secured to-the wall of the lbore of the respective pipe section so as to be permanently `and immovably fixed thereto. Infthe instance of the wireA for the upper pipe section P', its upper end, extends 'throughy the pipe to the collectorring 96 (Figure 6). From apoint where it enters the pipe it extends downwardly through the pipe and the conduit into and through a diagonal duct 99 (Figure 5)." This .duct 96 extends through the pipe and the box 99 of the joint J' to be intersectedby a duct 91am the box. At this point of intersection the wire 92 extends into duct 91 where it is welded to a lead 99, after which the duct 'is closed by a plug 99. A metal plug |99 permanently closes the lower end of the duct 99.

The lead 99 constitutes'part of a connector K and projects from a conducting strip |9| (Figure 4) disposed in a groove between the threads or the box 99. This strip is insulated from the to the pipe section P and provided with a brush From the rst collector ring 9 9 downwardly box by a strip` |92 to which it 'is secured by screws `|99 extending into .radial enlargements |94 of thestrip |92. These enlargements are tted insuitable recesses |99 in the box 99 to secure both strips |9| and |92 against circumferential shifting.`

That part of the connector K carried by the' pinv |96 of the joint J' comprises a contact stud |91 movably mounted in an insulator block |99 and urged intov contact with the strip 19| by a spring |99. As the 'strip |9| is disposed in the groove of the box 99 v,the contact studmust of necessity be disposed in the thread of the pin |06. To insure easy threading of the'pin in the box the pin thread is modified to accommodate i in parallel.

the stud and block as well as insulator strips I i0, H0. These strips extend in opposite directions from the block |08 (Figure 4) to insulate the conductor strip IOI from the pin |06. Screws I III and I I2 are employed to secure the block and strips in fixed position on the pin.

'I'hrough the spring |09 the stud |01 has electrical connection with the upper end of the wire 9% for the next pipe section below (Figure 5) which wire similarly extends into the bore of the pipe for connection to the wire for the next section below through a similar connector K. In this manner the wires of the conductor E are all insulated from the drill pipe and yet joined one to the .other by the several connectors until the conductor reaches the sub B. The connector K for the subis of theI same construction as the `other connectors, but the vwire without the conduit extends from the connector into afduct ||3 of the sub for connection to the wire 64 of the surveying instrument (Figure 7A).

Referring to Figure 11, I have here shown the drill pipe, the surveying instrument and the control means all incorporated in a circuit including a source of current such as the generator G, an ammeter A and a voltmeter V, all xof which latter are situated at the surface or topof the borehole. The voltmeter may be connected across the terminals of the generator as required by closure of a switch 4 for checking the. generator as to constant voltage. The ammeter A which is connectedsin series with the switch ||4, constitutes the registering instrument of the apparatus and registers modifications of current as controlled by the surveying instrument permanently situated in the sub of .the drill'pipe.

It will be understood that-the dial ofthe ammeter is calibrated in degrees of deviation so that the indicating hand thereof will accurately indicate the precise degree or minutes thereof of deviation.

By provision of a rheostat ||5 current flow through the ammeter A can be regulated to position the indicating hand thereof at zero degrees.

just prior to taking a survey. By a switch IIS the rheostat and the ammeter can be shunted to cause current to flow at the full voltage of the generator directly through the solenoid winding 29, and this winding is so designed as torequire a high voltage for operation of.its core. In Figure 11 the drill pipe of Figure 1 is represented by the wire ||`I to which the pendulum D and the winding 29 are electrically connected 'I'hus it is clear that the drill pipe constitutes one side of the electrical circuit, while the wire 64, the conductor E, and the connectors K constitute the other side. f

'I'he operation of the surveying apparatus is as follows:

During rotation of the drill pipe in the process of drilling a borehole, the pendulum is locked in the elevated and centered position shown in Figure 8, and thus the pendulum and its pivot are protected against damage by reason of the vibrating drill pipe. Preparatory to surveyinga borehole for maximum deviation the -drill pipe is first brought to a standstill, land .therithe indicating hand of the ammeter brought to a zero position by adjustment of the rheostat I5 following closure of the switch IIS only. I'he solenoid is now energized by momentary closureof the switch ||6 and4 momentary opening of the switch II4, thus .actuating the control'means to release the pendulum. The pendulum now gravicontinued rotation of the drill pipe or for al second survey, the switch ||6 is closed and the switch |I4 opened. Thus the solenoid is energized to elevate the pendulum to a locked and centered position with respect tothe commutator.

,In Figs. 13 to 23, is shown the second form of apparatus embodying my invention, which is characterized from the rst form in its ability to survey a borehole as to both direction and degree of deviation from the vertical. In Figs. 13-14 are shownthe surveying instruments and their appurtenances which are permanently positioned in the pocket 82 of the sub Bin place of the surveying instrument of the' first form of apparatus.

Referring to Figs. 13 and 14, the case ||8 is vclosed at,its two ends by plugs I I9 and |20, the

former of which is provided with a.- bearing |2I, receiving the lower end of a shaft |22 and a jewel thrust bearing |23, adjustable in the plug to denne the'lowermost position of the shaft.

The shaft is also journaled in a bearing |24 of a I disk |25 secured in fixed position within a. tube |20, the tube being fixed to the plug 9 in the manner illustrated.

Fixed to the shaft. |22 below the disk |25 is a compass |21 for turning the shaft, and below the compass and supported on the plug II9 is'a conventionai form of compensator |28. -Interposed between the compass and the disk is a 4coiled spring |28 for the purpose of locking the comm and shaft |22 against rotation when the two are elevated. Manifestly, when the compass is elevated, the spring is compressedto exert sufiicient pressure downward (on the compass to prevent rotation of the compass, and hence the shaft. Conversely, when the shaft is lowered, the spring is out of contact with the compass so that the latter 'is free to rotate the shaft.

Fixed to the shaft |22 at-a point abovethe disk |25 is a current distributor comprising a 55 cmmutator |20 and four sup rings, m, |32, |33,

'and |34. The commutatoris divided into four segments (Fig. 20) lwith a brush |35 for each segment. The slip ringsare each insulated-from ring (Fig. 21). All of the brushes are supported on but insulated from a suitable support |31 secured to the disk |25.

Fixed in the tube |28 above the commutator |30 is a second disk |30 through the center of which the shaft |22 extends and is journaled (Fig. 17). A coiled spring |40 is interposed be- .tween the disk and commutator to engage the latter when the shaft is elevated and thus aid the shaft |22, andthere is one brush I 36 for each '60 thelspring |20 'in securing the shaft against rota- |42, fuierumeaas et u2a on the disk las, to support the shaft in elevated position and the springs |20 and |40 compressed to lock the shaft against rotation. The disk is cut away as shown in Fig. 19 so as not to Vinterfere with the required` movements of the levers.

Springs 43 urge the levers upwardly, to cause rollers |44 `on the levers to engage cam wheels IThe cam wheels are fixed to a trans-V verse shaft |46, journaled in trunnions|41 depending from a frame |48 secured to the upper end of the tube |26. 'Ihe cam wheels are constructed the same as the camwheels 4|, and the same reference characters have been employed to designate the cams the depressions thereof..

Also xed to the shaft |46 is a pair of distributor wheels |49 and |50. Each wheel is constructed in the manner illustrated in Fig. 18, to provide a. plurality of radial contacts, any opposing two of which are engaged by two brushes- |43'L and |6011, respectively. However, as illustrated in Fig. 23, the' contacts of thesevwheels are arranged so that when the brushes for one wheel engage a pair of contacts, the brushes of the other wheel are out of engagement with their contacts, for a purpose to 'be described hereinafter.

Also fixed to the shaft |46 is a ratchet wheel I5| engaged by a pawl |52 pivoted on a lever |63 fulcrumed on the frame |48 by a pin |53"l and connected to the core |54 of a high resistance solenoid |55, secured to the disk |39. A spring |56 is connected to the pawl and to the disk for urging the pawl into engagement with the ratchet wheel. Manifestly, with energization of the solenoid |55, the pawl |52 is actuated' to rotate the shaft |46 a distance corresponding to the length of one tooth of the ratchet wheel |5I. The number of teeth on the ratchet wheel correspond to the number of depressions and cams on the. wheels |45, andthey in turn correspond in number to the contacts and intervening insulating segments of the wheels |49 and |50.

The cams 42 of the wheels |45 are adapted to engage and elevate a pair of cams |51, depending from a head |58, both of which are formed of insulating material. 'I'he cams |51 arev movable in slots of a uted disk |50 (Fig, 16) secured within the lower end of an upper tube |60 con-V tained within the. case H8. The disk is formed with a stud |6| extending into an opening |62 of the head |58, and provided with a pivot pin,

|63 forfa pendulum D'. Pins |62l guide the head |50 in its vertical movements. The pin |63 is adapted to engage within the bearing |64 of a weight |65 of the pendulum.

The pendulum also includes a rod |66 which is formed at its upper end with a sleeve |61, containing a spring-pressed brush or contact |68. This brush engages the. under side of a commutator C ilxed to the upper endl of the tube |60. The upper side of the head |58 is formed with a 'center and holding cup for the pendulum D', and thisV cup is provided with a chamfered surface |58at which, through engagement with a similar surface, |65a of the weight |65, functions to center the pendulum on'the pin |63 when the head is in the elevated position shown in Fig. 13.

A ring |65" of insulating material is secured within the tube |60, and secured Within the ring is Aa spring metal disk |65EL through the center of which the pinnacle of the weight |65 extends. The purpose of this disk is to limit upward movement of the pendulum and to cooperate with the head 50 in locking the pendulum against movementinany direction.

'I'he commutator C comprises a body |69 of insulating material having a concave underside concentric to the pendulum pivot. In this body is a central contact I 10 and a plurality of ring contacts |1|, each dividedfinto quadrants to form four segmental groups of contacts, as illustrated in Fig. 15. The contacts |1| of each segment are connected to a resistance unit |12 in the manner illustrated inv Fig. 23, and the four resistance units are'mounted on a drum |13 of insulating material, supported on the body |69 by means of a bracket |14. f

Also mounted in the drum |13 are four -resistance units |15, |16, |11, and |13, one for each of the slip rings |3I, |32, etc.; connected I thereto through their respective brush, |36, as shown in Fig. 23. A fth resistance unit |19 may be mounted on the drum |13 and connected in a circuit includingv all of the reslstances, |15, |16,

etc., through the distributor wheel |49, as shown in Fig. 23. This unit |19 corresponds in ohmic resistance to that of any one of the resistance units |12, for a purpose to be described herein-7 after.

'I'he compass |21, together with the commutator, slip rings and resistance units |15, |16, |11,-

and |18, constitute the instrument for surveying a borehole as to direction of deviation from the` movement and to release them the solenoid |55 4 must be energized. v'I'he solenoid, when energized, operates the pawl and ratchet mechanism to rotate the cam wheels |45 in lthedirection of the arrow in Fig. 13, to move the cams 42 out of engagement with the cams |51 so that the latter move into the depressions-43. Thus, rthe center.

lng head |58 is lowered to free the pendulum D' and permit it to repose on the pivot pin |63. The

.pendulum is now free to respond to any maximum deviation of the borehole from the vertical. According to the maximum angle assumed by the pendulum once it is released, determines the particular contact |1| of any segmental group, engaged by the pendulum contact |68.

Thus is determined the number of coils of any one resistance unit .|12 included in the circuit, of

which the rod |66 forms a part, it being clear from a considerationof Fig. 23 that when the contact |68 is vertical it engages the center con-4 tact |10 so that none of the resistance units |12 are included in the circuit. Also, depending upon the direction in which rthe pendulum swings from the center of the commutator, determines which resistance -unit |12 or any portion thereof, is included in the circuit.

With rotation of the cam wheels to release the pendulum, the cams 42 move oi the rollers |44 to permit the springs |43 to elevate the levers and move the rollers into the depressions 43. Thus the shaft |22 and the compass |21 are released to permit the shaft to be lowered in to the bearing |23 and the compass to rotate to a north position. Rotation of |the compass rotates the commutator and slip `rings to cause the segmentsof the commutator to respectively occupy the four cardinal n directions of the compass.

l In Fig. 23 is shown diagrammatically the registeringA instrument A' of the apparatus adapted for location at. the top of the borehole, together with a generator G Iand a control switch includbrated to indicate degrees of 'deviation'. Also,

the dial is provided with a ith division bearing the letter V fo ndi'cating the vertical position of a borehole'w en the hand in the ammeter points thereto; and a sixth division bearing the letter O tor indicating zero or the maximum resistance of the circuit.

In describing the operation of the apparatus, reference is had to Fig. 23, in which the circuits embodying the various instruments are illustrated. With the case ||8 permanently disposed in the pocket 82 of the sub B and the wires of the conductor E joined by the connectors K to form a continuous conductor corresponding to the wire |88 in Fig. 23, and the pendulum D' and the compass |21 both locked against movement, a survey of the borehole as to both degree and direction of deviation from the vertical is eiiected as follows:

First the drill pipe is brought to a standstill, and then from the neutral position shown the contact arm is moved to engage contact |88. Current from generator now flows through wire |89, contact arm |82, wire |90, ammeter A', wire |90, rheostat |81, drill pipe grounds |9|, and |92, wires |93, |94, and |95, wheel of distributor |49, wire |98, resistance |19, wires |91 and |98, all of the resistances |15, |18, etc., and back generator through Wire 88.

The circuit Just traced constitutes the testing and adjusting circuit in that the maximum resistance which the apparatus is capable oi' registering on the ammeter A' is connected thereto, and by adjustment of the rheostat |81, the indicatng hand of the ammeter can be brought to `a zero indication so that the current as subse- 'quently modiiled in accordance with degree and direction of deviation, will be registered accurately and irrespective of the electrical resistance oilered by the drill pipe and the conductor E as they are varied in length.

Following the above-described operation,the pendulum is released by moving contact arm |88 to engage drill pipe ground contact |84, when current iiows from generator through ground contacts |84 and |92, wire |98, winding of solenoid |55, and wires 200- and |88 back to generator. Thus the solenoid is connected directly to the generator so that its high'resistance winding is energized to move the core |88 and operate the control mechanism to release the pendulum and compass, and to actuate the distributors |48 and |50 to remove the resistance |18 from the circuit and interpose the commutator C' ltherein through a pigtail conductor 20| connected to the pendulum rod |60.

Once the instruments are released the solenoid, iS deenelgized and the ammeter included in the circuit by movement of contact arm 4|82 into engagement with contact |88.,l If the borehole is truly vertical, the pendulum contact |80 maintain-S engagement with the contact |10. so that current now ows from wire |88. contact arm |82, contact |88, wire |83b, wire |90, ammeter A'. Wire |90, rheostat |81, grounds |8| and |92, wires |98 and |94, wheel |50, conductor 20|', rod |88, contacts |89 and |10, wires 202 and |818 back to generator. Thus, the current traversing the ammeter A' is unmodiiled by the pendulum and so indicated by the hand of the ammeter pointing to division V, and thus indicating that th hole is vertical.

I1' this borehole is not lvertical the commutator C' moves in relation to the pendulum so that the pendulumA contact |88 now engages that contact |1| which is vertically thereabove and of that segmental group tacingthe direction of deviation oi' the borehole. The compass having been released, it moves to and maintains a north position irrespective of the circumferential position of the commutator C', thereby locating the four segments oi the master commutator |80 with the cardinal. points of. the compass. In doing this, the segments of the commutator are electrically connected to the segments of the commutator C' so that the latter are now directionally located with respect to the cardinal points of the compass. i, Through the electrical connections between the segments oi' the commutator, the slip rings |84, and the resistance units |15, |18, |11, and |18, vthese resistance units can be selectively interposed in the circuit with any one of the commutator resistances |12 in any combination, depending upon the directional position of that segment of the commutator C' which is engaged by the pendulum contact. For example, if. the borehole is deviating in a westerly direction, the pendulum contact |88 will engage any one of the contacts |1|, depending upon the maximum degree of deviation, of that segmental group positioned ina westerly direction. 'I'hus a. corresponding portion of the nespective resistance |12 is removed from the circuit to modify the current traversing the ammeter accordingly and thereby indicate on the ammeter the degree of deviation.

The westerly direction of deviation is indicated on the ammeter by including in the circuit all resistances |15, |18, etc. through the following f contact |1|, resistance |12, wire 203, segment f |30W of commutator |30, wire 204, subsidiary commutator |34, wire |98, resistances |18 to'l18, and wire- |88 to generator.

With all resistances |18 to |18 included in the circuit, the amplitude of movement of the ammeter hand is confined to division W thereof. thus indicating that the borehole is deviating in a westerly direction. Manifestly, the degree of deviation is indicated by the position of the ammeter hand within the divisionl W as controlled by that portion of the resistance |12 remaining in the circuit as determined by the pendulum.

From the foregoing example, it'will be clear that if. on the other hand, the borehole deviates ina southerly direction, an easterly direction, or a northerly direction, the resistances |15, |18, and 11 respectively, will be removed from the circuit thereby modifying the current accordingly to limitA the amplitude of movement of the ammeter hand to the respective dial division and thus indicating the cardinal direction of deviation. This is supplemented by the precise positioning of the hand in any one division to indicate the degree of deviation in accordance with the current as further modified by the respective resistance |12.

Following any directional and degree of deviation reading the parts of the apparatus may be restored to a normal position by moving the arm |82 momentarily into engagement with contact |86 and then back to neutral position when the solenoid |55 is again energized to restore the two surveying instruments to locked positions and-rotate the distributor wheels |49 and |50 to the positions shown in Fig. 23. Thus the apparatus is ready for a second survey of the borehole when desired, and the drilling operation may be continued without damage to the apparatus. y

I claim: y

1. A drill pipe having longitudinally and diametrically opposed portions thickened transversely, one of said portions being formed with a pocket adapted for the reception of a hole surveying instrument.

2. In a borehole survey apparatus; an electric instrument sensitive to deviation; a second electric instrument sensitive to direction of deviation; and electriccontrol means for the two instruments by which they can be locked or released.

3. In a borehole survey apparatus; gravityoperated electrical-resistances each variable as to deviation from'the vertical and'one resistance A,

for each compass point; an electrical resistance variable as to direction of deviation from the vertical; and compass-operated means for connecting the last mentioned resistance to any one of the gravity-operated resistances so that the two resistances are combined and the sum varied in accordance with degree and direction of deviation.

4. In a borehole survey apparatus; gravityoperated electrical resistances each variable as to deviation from the vertical and one resistance for each compass point; an electricaliresistance variable as to direction of deviation from the vertical; compass-operated means for selecting a variable resistance'as to direction for connection with one of the deviation resistances; and' an ammeter correlated to said resistances so as to visibly indicate the degree and direction'of deviation. y

5. In a borehole survey apparatus; a master commutator having four conducting segments corresponding to the cardinal points; a shaft to which the commutator is xed: four slip rings :iixed to the shaft and electrically connected respectively to the four segments; electrical resistances, one for each of the slip rings and electrically connected thereto; and a compass iixed to the shaft. i

6. In an apparatus for surveying boreholes; the combination of a drill stem; a stationary commutator within the drill stem; a pendulum within the drill stem having a contact engaging the commutator, and a support in the drill stem by which the pendulum is gravity-actuated to move the contact over the commutator; and means in the drill stem for elevating the pendulum off of its support and locking it against movement in relation to the commutator.

7. In combination; a sectional and tubular drill pipe, one section of said pipe having a pocket therein and between the walls thereof so as to be oiset with relation to the major axis of the bore of said section; a hole surveying instrument in said pocket for modifying electric cur-` rentl in accordance with inclination of said pipe section; current modification indicating means situated adjacent the top of said drill pipe; and a circuit in which said instrument and said means are located, said circuit including conductors secured to one wall o f the drill pipe sections and detachably connected to each other at the joints betweensaid sections.

8. An apparatus for surveying wells, comprising in combination with a sectional drill pipe; an electric survey device in the drill pipe between the inner and outer walls thereof, said device being sensitive to inclination and direction of inclination; inclination and direction of inclination indicating means at the surface of the well; and a circuit in which said device and means are located, said circuit including conductors secured to one Wall of the drill pipe sections and detachably connected to each other at the joints between said sections.

9. An apparatus for surveying Wells, comprising in combination with a sectional drill pipe; an electric survey device in the drill pipe between the inner and outer Walls thereof, said device being sensitive to inclination; inclination indicated, said circuit including conductors secured to one wall of the drill pipe and detachably connected to each other at the joints between the sections.

10. An apparatus for surveying wells, comprising in combination with a sectional drill pipe; an electric surveydevice in the drill pipe between the inner and the' outer Walls thereof, said device being sensitive to direction of inclination; direction of inclination indicating means at the surface ofthe well; and a circuit in which said device and said means arelocated, said circuit including conductors secured to one wall of the drill pipe sections and detachably connected to each other at the joints between said sections.

ARTHUR R. BARNE'II. 

